Hi, Experts:
In my crontab, I have the following line:
05 7-16 * * 1-5 /home/scripts/check_mirror_server

The check_mirror_server script is the following:
What the script does --> ps -ef to check mirroring process, expect 4 processes. If less the 4, check which one is death and restart it (I only put one restart here)
#!/bin/bash
#
cd /home/scripts
lc=$(ps -ef | grep -cE '[0-9]{2}:[0-9]{2}:[0-9]{2} ./mirror o server2')
if ((lc != 4));
then
mail admin@mycompany.com -s "Redundent Server Has Problem, count $lc" < <(ps -ef | grep "mirror o server2")
ps -ef | grep -qE '[0-9]{2}:[0-9]{2}:[0-9]{2} ./mirror o server2 7300'
if [ $? = 1 ]
then
nohup /AppHome/rc8mirout
mail admin@mycompany.com -s "Redundent Server has been restarted" < /home/scripts/MirrorProMsg
fi
fi

The script itself works fine. But it created a defunct process after it restart the mirroring process
#ps -ef | grep 22979
root 22979 2307 0 07:05 ? 00:00:00 crond
root 22981 22979 0 07:05 ? 00:00:00 [check_mirror_se] <defunct>

Would anybody tell me where I did wrong in my script to cause this defunct process?
Thank you very much!

Does this happen only under cron or when you execute manually also?

Assuming you have tested from the command line then three things come to mind.

Firstly the environment set up by cron to run your script is not the same as the login environment. You can determine whether this is causing the problem by changing the seccond line of your script toThat "l" is a letter. It tells bash to simulate the login process.

Secondly, if the script writes anything to stdout or stderr (these will normally appear on the terminal when running interactively) then that will break a cron job.

Thirdly the < < is weird in
Here's how to mail output from ps -ef | grep "mirror o server2" without redirection Here the double quotes around mirror o server2 have been replaced with single quotes for simplicity and 2>&1 has been added to redirect any stderr (which would break the cron job) to stdout so it is mailed along with the stdout from ps -ef | grep 'mirror o server2'

The problem only happen under cron job.

I follow Catkin's suggestion:
1) add -l to this line ==> #!/bin/bash -l
2) I don't think I have any stdout or stderr from the script except this ==> "nohup /AppHome/rc8mirout", from vendor and I have no idea if it will have any stdout or stderr

3)The following line:
mail admin@mycompany.com -s "Redundent Server Has Problem, count $lc" < <(ps -ef | grep "mirror o server2")
The -s "Redundent Server Has Problem, count $lc" is supposed to go to subject line. The weird redirect < <(ps -ef | grep "mirror o server2") is suppsed go to the email body.

I could be wrong, but the following line seems everything go to the subject line.
mail admin@mycompany.com -s "Redundent Server Has Problem, count $lc $(ps -ef | grep 'mirror o server2' 2>&1)"

But I eliminated the weird redirect for now.

Finally, I add the >/dev/null 2>&1 to the cron job line
05 7-16 * * 1-5 /home/scripts/check_mirror_server >/dev/null 2>&1

Now, I run under test mood (comment out the "nohup /home/fsi/rc8mirout" and change the condition), and it seems working (no defunct process was created).

Thank you for all your help and your suggestions.
Thank you again.

Of course it does! The mail command wants the body of the mail from stdin. Sorry for my error. How did you solve it? If I'd realised I might have suggested

Catkin:
For testing purpose, I eliminated the weird redirect completely in case it cause problem first. After I tested it and made sure the cron job didn't create any defunct process, I put it back as it was, and it worked.

But I think your code is cleaner and look nicer. I will use your code instead. I didn't know where I got the idea of the weird redirect.

Thank you very much!

Catkin:

I tried your code, it gave me syntax error: unexpected end of file.
========
mail admin@mycompany.com -s "Redundant Server Has Problem, count $lc" <<EOF
$(ps -ef | grep 'mirror o server2' 2>&1)"
EOF
========
First, I think the double quotes are mis-matched. But I am not sure if I need to remove one or add one. I tried to add a double quote right after the first EOF, but got the same syntax error.

Any suggestion?
Thank you very much!

The double quotes are mis-matched. Add a double quote in front of $(

Intriguing that the "weird" redirect (< space <) works!

Catkin:
You really got me curious. The code you suggest is not working. I simplified it to the following:

#!/bin/bash -x
#
mail admin@mycompany.com -s "Redundant Server Has Problem, count $lc"
<<EOF
"$(ps -ef | grep 'mirror o server2' 2>&1)"
EOF

When I run it from the command line (the script called check_mirror), it stop after the mail command. I have to Ctrl/C couple of times, then the "ps -ef" appeared and finished.

#./check_mirror
+ cd /home/deng/scripts
+ mail admin@mycompany.com -s 'Redundant Server Has Problem, count '


(Interrupt -- one more to kill letter)
++ ps -ef
++ grep 'mirror o server2'

Any suggestions?
Thank you very much!

I'm sorry you are having such a hard time and thank you for your patience (especially with my mistakes!).

You need this format, so the "here document" is fed into the mail command as if you had entered it from the keyboard

After I stared the screen output for a while, I suddenly recognized the mail command is waiting for a input. As soon as I put the <<EOF in the same line with the mail command (just like what you suggested), the simplified script works. I am going to put it to the real script for testing.
Thank you very much!